A method for the determination of lathanum, praseodymium, neodymium and samarium oxides in cerium dioxide has been developed.
The sample in the oxalate form is mixed with the binding material (boric acid) in the ratio 1∶1 pressed to form a double layer
pellet over a boric acid backing pellet and irradiated by X-rays from a tungsten tube. The secondary X-rays are dispersed
with a LiF (200) crystal in a Philips PW 1220 semiautomatic X-ray fluorescence spectrometer. The intensity of fluorescent
X-rays is measured by a flow proportional counter. The minimum determination limit is 0.01% for lanthanum and samarium oxides
and 0.02% for praseodymium and neodymium oxides. The precision at each concentration of the standards and theoretical minimum
determination limit for each element have been calculated.
Authors:A. Souza, M. Oliveira, I. Santos, M. Conceição, L. Nunes, and J. Machado
The kinetics of thermal decomposition of solid In(S2CNR2)3 complexes, (R=CH3, C2H5, n-C3H7,i-C3H7, n-C4H9 and i-C4H9), has been studied using isothermal and non-isothermal thermogravimetry. Superimposed TG/DTG/DSC curves show that thermal
decomposition reactions occur in the liquid phase, except for the In(S2CNMe2)3 and In(S2CNPri2)3 compounds.
Authors:L. Machado, A. Marins, E. Muri, A. Biondo, J. Matos, and I. Mazali
Reactions in aqueous-alcoholic solution between diphenyl-4-amine barium sulphonate (Ba-DAS—anionic surfactant) and the hydrated
sulphates of Fe(III) and Fe(II) ions and their use to ovtain iron oxides are described here. The formation of Fe(II) complexes
was reached by using an excess of Ba-DAS, in absence of light under inert atmosphere. The complexes achieved Fe2[(C12H10NO3S)4]·9H2O and Fe3[(C12H10NO3S)6]·12H2O were characterized by TG/DTG and IR, UV-VIS and 57Fe-Mössbauer analyses.
Authors:O.N. Campas-Baypoli, D.I. Sánchez-Machado, C. Bueno-Solano, A.A. Escárcega-Galaz, and J. López-Cervantes
Moringa oleifera tree has been recognized internationally for its nutritional, therapeutic and medicinal properties. Dry seeds are rich sources of oil with a high potential of commercial exploitation. The present study reports the physicochemical characterization, polyphenol content, DPPH radical scavenging capacity and fatty acid profile of moringa seed oil, and the chemical composition of the seed cultivated in Sonora, Mexico. Moisture, ash, protein and lipid contents in the seed were found to be 4.7, 5.8, 26 and 39%, respectively. The oil showed a refractive index of 1.4642. The saponification number was 183 mg KOH/g oil, iodine value: 75 g I/100 g of oil, acid value: 0.49 (% oleic acid). The polyphenol content was 0.137 mg of gallic acid equivalent/g and DPPH radical scavenging capacity was 87.39%. The moringa seed oil was rich (68%) in the major fatty acid, oleic acid (C18:1n9). Moringa oil extracted by sonication showed a fatty acid profile and physicochemical properties comparable to the oil from seeds grown in different regions of the world. The optimization of the oil extraction process on a large scale shows high potential, as the oil could be marketed as edible vegetable oil, for frying purposes, or as a functional ingredient.